For some time, a unique excited state of the oxygen molecule has been known to have a relatively long half life. The excitation energy of this species is approximately 1 electron volt, and the half life about 40 minutes. This species has been used as an energy source for Iodine/Oxygen chemical lasers. This species is known in the prior art as "Delta Singlet Oxygen" (see for instance "Chemically Pumped Iodine Laser", by R. J. Richardson and C. E. Wiswall, Appl. Phys. Lett. 35(2), July 1979).
In a pending application, the use of this species to stabilize oxygen content in certain high temperature oxide ceramic superconducting layers was shown. "Delta Singlet Oxygen" in can also be used accurate "milling" of diamond-like carbon insulating layers by plasma etching as the reactive gas.
"Delta Singlet Oxygen" is formed in the following reaction: EQU H2O2+2KOH+Cl2(1)=O2(1.DELTA.)+2KCl+H2O
In principle, any other hydroxide of the alkali metals (particularly NaOH, see Richardson et. al.) could be used as well, but at the high concentrations required to obtain an efficient "Delta Singlet Oxygen" production rate, potassium hydroxide has been determined to be most suitable, due to the lower viscosity of the solution and thus the ease of atomization.
In the prior art, the combination of hydrogen peroxide with potassium hydroxide in solution was used as the working medium in which chlorine gas was simply bubbled through. "Delta Singlet Oxygen" exudate was collected above this solution. This technique, often termed the "bubbler reactor", has had a number of major shortcomings.
The flow rate of chlorine is strongly limited, since too high a flow rate produces unreacted chlorine that can be deleterious (if not for Iodine/oxygen lasers, certainly for the purpose of depositing and etching superconducting electronic devices). Furthermore, excessive eruption of unreacted chlorine drastically disrupts the surface of the liquid and causes excessive interaction of the solution with the already created "Delta Singlet Oxygen". Obviously, this causes premature deactivation of the "Delta Singlet Oxygen".
In a typical bubbler, "Delta Singlet Oxygen" bubbles created near the interaction zone of the chlorine with the hydroxide and peroxide must travel to the top of the liquid. If the flow rate of the chlorine is very slow, then the bubbles are small and the surface area large. This results in deactivation due to contact with the liquid. If the bubbles are too large, the reaction rate is slow and some free chlorine will reach the surface. Decreasing the column of liquid above the bubbling source is not helpful either, since this action results in a decrease of the reaction path. Drip reaction on wet columns is also part of the prior art, and it's major shortcoming is low yield due to the small available surface area.